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Ecological-Based Mining:A Coal-water-Thermal Collaborative Paradigm in Ecologically Fragile Areas in Western China

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engineering 2024年第7期38卷 209-222页

作者： Xiaoxiu Liu Yifan Zeng Qiang Wu Shihao Meng Jiyue Liang Zhuping Hou National engineering research Center of Coal Mine water Hazard Controlling China University of Mining and TechnologyBeijing 100083China College of Geoscience and Surveying engineering China University of Mining and TechnologyBeijing 100083China University of Mining and technology(beijing)Inner Mongolia research Institute Ordos 017000China

A substantial reduction in groundwater level,exacerbated by coal mining activities,is intensifying water scarcity in western China’s ecologically fragile coal mining ***’s national strategic goal of achieving a carbon peak and carbon neutrality has made eco-friendly mining that prioritizes the protection and efficient use of water resources *** on the resource characteristics of mine water and heat hazards,an intensive coal-water-thermal collaborative co-mining paradigm for the duration of the mining process is *** integrated system for the production,supply,and storage of mining companion resources is achieved through technologies such as roof water inrush prevention and control,hydrothermal quality improvement,and deep-injection geological *** active preventive and control system achieved by adjusting the mining technology and a passive system centered on multiobjective drainage and grouting treatment are suggested,in accordance with the original geological characteristics and dynamic process of water *** implementing advanced multi-objective drainage,specifically designed to address the“skylight-type”water inrush mode in the Yulin mining area of Shaanxi Province,a substantial reduction of 50%in water drillings and inflow was achieved,leading to stabilized water conditions that effectively ensure subsequent safe coal *** integrated-energy complementary model that incorporates the clean production concept of heat utilization is also *** findings indicate a potential saving of 8419 t of standard coal by using water and air heat as an alternative heating source for the Xiaojihan coalmine,resulting in an impressive energy conservation of 50.2%and a notable 24.2%reduction in carbon *** ultra-deep sustained water injection of 100 m^(3)·h^(-1)in a single well would not rupture the formation or cause water leakage,and 7.87×10^(5)t of mine water could be effectively stored in the Liujiagou Formation,presenti

关键词： Dual carbon targets Coal-water-thermal co-mining Ecologically fragile areas Mine-water control Resource utilization

New Hybrid CHP system Integrating Solar energy and Exhaust Heat Thermochemical Synergistic Conversion with Dual-Source energy Storage

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Journal of Thermal Science 2024年第3期33卷 970-984页

作者： QIN Yuanlong LIU Taixiu LI Peijing ZHAO Kai JIAO Fan PEI Gang LIU Qibin Department of Thermal Science and energy engineering University of Science and Technology of ChinaHefei230027China Institute of engineering Thermophysics Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China School of energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

For the efficient use of solar and fuels and to improve the supply-demand matching performance in combined heat and power(CHP)systems,this paper proposes a hybrid solar/methanol energy system integrating solar/exhaust thermochemical and thermal energy *** proposed system includes parabolic trough solar collectors(PTSC),a thermochemical reactor,an internal combustion engine(ICE),and hybrid storage of thermal and chemical energy,which uses solar energy and methanol fuel as input and outputs power and *** methanol thermochemical decomposition reaction,mid-and-low temperature solar heat and exhaust heat are upgraded to chemical energy for efficient power *** thermal energy storage(TES)stores surplus thermal energy,acting as a backup source to produce heat without emitting CO_(2).Due to the energy storage,time-varying solar energy can be used steadily and efficiently;considerable supply-demand mismatches can be avoided,and the operational flexibility is *** the design condition,the overall energy efficiency,exergy efficiency,and net solar-to-electric efficiency achieve 72.09%,37.65%,and 24.63%,*** fuel saving rate(FSR)and the CO_(2) emission reduction(ER_(CO_(2)))achieve 32.97%and 25.33%,*** research findings provide a promising approach for the efficient and flexible use of solar energy and fuels for combined heat and power.

关键词： hybrid energy system solar thermochemical exhaust heat energy storage operational flexibility

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A general two-phase mixture model for sediment-laden flow in open channel

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Journal of Hydrodynamics 2022年第2期34卷 286-298页

作者： Jia-xing Li Xin Chen beijing engineering research Center of safety and energy saving technology for water supply network system China Agricultural UniversityBeijing100083China

This work extends the sediment-laden mixture model with consideration of the turbulence damping and particle wake effects under the framework of improved efficiency and *** mixture model consists of the continuity and momentum equations for the sediment-laden mixture,and the continuity equation for the sediment.A theoretical formula is derived for the relative velocity between the water and sediment phases,with consideration of the effects of the pressure gradient,the shear stress and the lift force.A modified expression of the particle wake effect,inducing the local turbulence enhancement around the sediment particle,is employed to improve the turbulent diffusion of the coarse *** k_(m)-ε_(m) model is proposed to close the mixture turbulence,with the turbulence damping effect due to the high sediment concentration expressed by the density-stratification term without an empirical *** k_(m)-ε_(m) turbulence model requires smaller computational work and offers better results than an empirical density-stratification turbulence model in high sediment concentration ***,with the proposed mixture model,the sediment transport in the open channel under a wide range of sediment sizes and concentrations can be revealed with the results in good agreement with experimental data for the velocity,the sediment concentration and the turbulent kinetic energy.

关键词： Sediment-laden flow two-phase mixture model particle wake effect turbulence damping effect density stratification

Mobile bed thickness in skewed asymmetric oscillatory sheet flows

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Acta Mechanica Sinica 2018年第2期34卷 257-265页

作者： Xin Chen Yong Li Fujun Wang beijing engineering research Center of safety and energy saving technology for water supply network system China Agricultural University Tianjin centre China Geological Survey

A new instantaneous mobile bed thickness model is presented for sediment transport in skewed asymmetric oscillatory sheet flows. The proposed model includes a basic bed load part and a suspended load part related to the Shields parameter, and takes into account the effects of mass conservation, phase-lag, and asymmetric boundary layer development, which are important in skewed asymmetric flows but usually absent in classical models. The proposed model is validated by erosion depth and sheet flow layer thickness data in both steady and unsteady flows, and applied to a new instantaneous sediment transport rate formula. With higher accuracy than classical empirical models in steady flows, the new formula can also be used for instantaneous sediment transport rate prediction in skewed asymmetric oscillatory sheet flows.

关键词： Mobile bed thickness Phase-lag Sediment transport Sheet flow Skewed asymmetric oscillatory flow

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General velocity formula of boundary layer above mobile sediment bed induced by asymmetric waves

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International Journal of Sediment research 2021年第2期36卷 255-267页

作者： Xin Chen Minghong Chen beijing engineering research Center of safety and energy saving technology for water supply network system China Agricultural University

Sediment movement in the wave boundary layer above a mobile sediment bed is complex. A velocity formula for the boundary layer is proposed for sheet flow induced by asymmetric waves above a mobile sediment bed. The formula consists of a free stream velocity and a defect function which contains a phase-lead, boundary layer thickness and mobile sediment bed. Phase-lag of sediment movement is considered in the formula for the mobile sediment bed. The formula needs six dependent variables about asymmetric wave and sediment characteristics. Asymmetry effects on parameters(orbital amplitude,roughness height, bed shear stress, and boundary layer thickness) are properly considered such that the formula can yield velocity differences among onshore, offshore, acceleration, and deceleration *** formula estimates the net boundary layer velocity resulting from the mobile sediment bed and asymmetric boundary layer thickness. In addition, a non-constant phase-lead also contributes to the net boundary layer velocity in asymmetric oscillatory sheet flow. Results of the formula are as good as that of a two-phase numerical model. Sheet flow transport induced by asymmetric waves, and the offshore net sediment transport rate with a large phase-lag under velocity-skewed waves, can be adequately estimated by the formula with a power sediment concentration function.

关键词： Asymmetric wave Boundary layer Mobile sediment bed Sheet flow Velocity formula

Analytical approach for sheet flow transport in purely acceleration-skewed oscillatory flow

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International Journal of Sediment research 2018年第3期33卷 234-242页

作者： Xin Chen Fujun Wang Xuelin Tang beijing engineering research Center of safety and energy saving technology for water supply network system China Agricultural University

An instantaneous analytical approach is developed to predict sheet flow transport in purely accelerationskewed oscillatory flow. The approach is derived from exponential approximations of velocity and concentration profiles above a mobile seabed, and it particularly considers factors of phase lead; phase lag(i.e. phase residual and phase shift); acceleration modification; and asymmetries in shear stress,roughness height, and boundary layer development. The approach can predict net boundary layer flow above a mobile seabed, and can revert to the classical bedload model. Instantaneous and net sediment transport rates are studied using the approach. The instantaneous sediment transport rate in an onshore flow stage can be approximated by a power function of velocity in which the exponent is confirmed to range between 1 and 5 with a decrease in the phase residual. The net sediment transport rate predicted using the approach is validated using a considerable amount of measured data, and compared with existing instantaneous and half-period type models that consider the phase lag or acceleration modification. For the net sediment transport rate in purely acceleration-skewed oscillatory flow, the phase residual is less important than the acceleration-skewed boundary layer difference between onshore and offshore acceleration stages.

关键词： Analytical approach Sheet flow Acceleration-skewed oscillatory flow Phase lag Boundary layer flow

Deflection of cavitation bubble near the rigid wall with a gas-containing hole

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Journal of Hydrodynamics 2023年第2期35卷 330-337页

作者： Yu-rong Sun Qiang Zhong Zhi-feng Yao Dan Zi Ruo-fu Xiao Fu-jun Wang College of water Resources and Civil engineering China Agricultural UniversityBeijing100083China beijing engineering research Center of safety and energy saving technology for water supply network system Beijing100083China

The presence of a rigid wall causes a microjet of the cavitation bubble to collapse to move toward the wall,while a free surface does the *** a rigid wall surface is combined with a free surface,it may affect the direction of the *** motive of this study is to find out the influence of the dynamic behavior of a laser-induced bubble near the rigid wall with a gas-containing *** of the bubble at different distances from the gas-containing hole in the horizontal and vertical directions were recorded by a high-speed camera(2.3×10^(5) fps).When the bubble collapse near the boundary,the bubble will produce two situations:away from or toward the *** focuses on the direction of the bubble,the oscillation period of a bubble,and reflection angle,and quantitative analysis of the *** was found that the boundary not only changes the morphologic of the bubble and the overall direction of movement but also affects the oscillation *** addition,it can control the deflection of the bubble.

关键词： Cavitation bubble bubble migration deflection angle gas-containing hole

Experimental Investigation of Flow Patterns in a Pump Intake with Different CWL(Critical water Level)and Back-Wall Clearance

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Journal of Thermal Science 2021年第6期30卷 2150-2163页

作者： GUO Miao TANG Xuelin LI Xiaoqin WANG Fujun College of water Resources and Civil engineering China Agricultural UniversityBeijing 100083China beijing engineering research centre of safety and energy saving technology for water supply network system China Agricultural UniversityBeijing 100083China

In this study,influence of back-wall clearance,CWL(Critical water Level)and air content in water on flow patterns in a pump intake has been investigated experimentally and theoretically for different *** statistical data show that CWL for a two-phase flow is lower than that in the case of a single-phase flow at a relatively low flow rate,and as the flow rate increases,this trend turns out to be completely *** experimental data obtained under conditions of subcritical,critical and supercritical flow rates have revealed that the larger the back-wall clearance is,the more vortices exist and the higher the vorticity of free-surface vortices *** the smallest back-wall clearance,the flow coming through the inlet occupies most space under the pipe bell,and both this flow and the inflow coming from the back wall are asymmetric relative to a certain vertical line other than the *** the larger and the largest back-wall clearances,the flows coming from the inlet and from the back wall are almost symmetrical relative to the vertical axis of the pipe *** velocity distributions on two PIV measurement lines for different back-wall clearance magnitudes indicate that the smallest back-wall clearance influences the flow around the pipe bell.

关键词： Critical water Level(CWL) back-wall clearance air content in water pump intake

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A novel Omega-driven dynamic PANS model

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Journal of Hydrodynamics 2020年第4期32卷 710-716页

作者： Chao-yue Wang Fu-jun Wang Ben-hong Wang Yuan Tang Hao-ru Zhao College of water Resources and Civil engineering China Agricultural UniversityBeijing 100083China beijing engineering research Center of safety and energy saving technology for water supply network system Beijing 100083China

A novel Omega(Ω)-driven dynamic partially-averaged Navier-Stokes(PANS)model is proposed in this *** ratio of the modeled-to-total turbulent kinetic energies fk is dynamically adjusted by the rigid vorticity ratio(the ratio of the rigid vorticity to the total vorticity),the key parameter of the Ω vortex identification *** classical flow cases with rotation and curvature are used to test the *** results show that the turbulent viscosity is effectively adjusted by the new dynamic fk and the LES-like mode is activated,which can help the revelation of more turbulence information and improve the prediction *** new PANS model does not contain any explicit dependency on the grid size and enjoys good adaptability to the flow fields,and can be used for efficient engineering computations of the turbulent flows in the hydraulic machinery.

关键词： Dynamic partially-averaged Navier-Stokes(PANS) turbulence model Omega engineering computations